Without limiting the scope of the invention, its background is described in connection with methods of stabilizing curcumin and THC in plasma and bile against degradation occurring during analytical processes. Curcumin is the major yellow pigment of turmeric, derived from the rhizome of the herb Curcuma longa Linn, and has traditionally been used as a treatment for inflammation, skin wounds, and tumors. In addition, preclinical animal models, curcumin has shown cancer chemo preventive, antineoplastic and anti-inflammatory properties. Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] has the structure below:

Curcumin acts as a scavenger of hydroxyl radical, superoxide anion and singlet oxygen and other oxygen species. Curcumin plays a role in cellular signal induction pathways pertinent to growth, differentiation and malignant transformations, including inhibiting protein kinases, c-Jun/AP-1 activation, prostaglandin biosynthesis, and may play a role in the activation of the transcription factor NF-κB. However, it has been thought that the bioavailability of curcumin in animals remains low with a poor bioavailability which may be related to its inadequate absorption and fast metabolism. Indirect evidence suggests that curcumin is metabolized in the intestinal tract where curcumin undergoes metabolic O-conjugation to curcumin glucuronide and curcumin sulfate and bioreduction to THC, hexahydrocurcumin and hexahydrocurcuminol. Much of this is confirmed through examination and analysis of curcumin present in samples (e.g., tissue extracts) before and after treatment. In studies it has been shown that perorally administered curcumin has poor bioavailability and only low or non-measurable blood levels were observed. Others have administered piperine along with curcumin to enhance the bioavailability of curcumin; however, the level of enhancement was only modest and no curcumin could be detected after 3 hours even when supplemented with piperine.
U.S. Pat. No. 8,153,172, entitled “Composition to Enhance the Bioavailability of Curcumin,” discloses a composition having a curcuminoid and an essential oil of turmeric. A composition having a curcuminoid and an essential oil of turmeric, wherein the essential oil is present in an amount sufficient to cause an enhancement of bioavailability of curcumin when the composition is administered to a human as compared to bioavailability of curcumin obtained upon administration of a composition prepared without adding essential oil to the curcuminoid. A method to prepare a composition having a curcuminoid and an essential oil of turmeric.
U.S. Pat. No. 7,067,159, entitled “Methods for Treating Prostate Cancer with Herbal Compositions,” discloses methods for treating prostate cancer, comprising administration of a composition comprising therapeutically effective amounts of supercritical extracts of rosemary, turmeric, oregano and ginger; and therapeutically effective amounts of hydroalcoholic extracts of holy basil, ginger, turmeric, Scutellaria baicalensis, rosemary, green tea, huzhang, Chinese goldthread, and barberry.
U.S. Pat. No. 7,060,733, entitled “Methods for Treating Pancreatitis with Curcumin Compounds and Inhibitors of Reactive Oxygen Species,” discloses methods of treating, preventing, modulating, attenuating, or inhibiting a disease or a disorder associated with inflammation related to NF-κB activation in a subject which comprises administering to the subject at least one curcumin compound. Also disclosed are combination therapies comprising the administration of at least one curcumin compound and at least one ROS inhibitor. Pharmaceutical compositions and kits are also disclosed.
U.S. Pat. No. 5,679,864, entitled “Process for the Synthesis of Curcumin-Related Compounds,” discloses a process for the synthesis of curcumin and curcumin-related compounds by reacting the enol form of a 2,4-diketone with a monocarbocyclic aldehyde in the presence of an organic amine catalyst. The reactants are dissolved in a highly polar, aprotic organic solvent. The curcumin-related product is recovered in crystalline form by precipitation from the reaction mass and solvent recrystallization.